Fertilize and Overseed Tall Fescue - Ask Extension
Hello!
I am a new homeowner and want to take care of my tall fescue. Because we get a lot of leaves down in the fall, I am thinking about fertilizi...
Knowledgebase
Fertilize and Overseed Tall Fescue #896255
Asked April 03, 2025, 10:09 AM EDT
Hello!
I am a new homeowner and want to take care of my tall fescue. Because we get a lot of leaves down in the fall, I am thinking about fertilizing and overseeding in the spring (hopefully this week). It is a well-established lawn with some bare spots. When should I fertilize and seed? Should I do them at the same time? Should I seed the whole lawn, even the well-established parts? Could you also please recommend a fertilizer to use, given that I have not tested the soil? Any other lawn care tips for newbies are appreciated! Thank you so much!
Montgomery County Maryland
Expert Response
Spring seeding can be more challenging, as the ideal time of year for fescue seeding/overseeding is late summer through early autumn (about September). It can be done now if needed to repair thin areas, though there might be more issues with weeds. If any areas are more extensively bare, laying sod (once any leftover grass is cleared off) would be more practical and easier to establish. Both seed and sod need careful attention to watering, as they won't tolerate drying out too much as they establish.
For now, focus on seeding only thin or bare areas. Overseeding for the whole lawn should be done only in autumn.
Fertilizer application can wait until closer to May (maybe around 3-5 weeks after sowing the seed), in part because the new grass roots won't access those nutrients in the soil well enough until they're more established, and because any organic components of a fertilizer are broken-down by soil microbes, which aren't very active until the soil temperatures are warmer.
You'll need the results of a laboratory soil test to determine if you can (legally) use a lawn fertilizer formulation that has phosphorus in it (the P in the N-P-K nutrient analysis). If the test shows a P deficiency, then you can use a "starter" fertilizer (which will have P in it); if not, then a P-free fertilizer would be needed. We can help to interpret soil test results if desired. (Testing is mainly used for learning the nutrient content and acidity/pH. The lab will probably return some auto-generated fertilization recommendations along with the results, but bear in mind that they don't necessarily adjust those recommendations to comply with Maryland law, so use the UMD fertilization rates as your guide. The lab will also typically provide lime application rates if the pH needs adjusting, and those are fine to use as given.)
We have many web pages about all aspects of lawn care and maintenance that you can explore. They focus on tall fescue since that is the grass type recommended for most Maryland yards. In the coming months, we hope to drastically consolidate our lawn content into new web pages, but when that happens, we will try to have all of the old web page addresses redirect to the new pages; or, the content will still be easy to find, so you won't miss out on it if you need to check it again closer to lawn care season in autumn.
Miri
For now, focus on seeding only thin or bare areas. Overseeding for the whole lawn should be done only in autumn.
Fertilizer application can wait until closer to May (maybe around 3-5 weeks after sowing the seed), in part because the new grass roots won't access those nutrients in the soil well enough until they're more established, and because any organic components of a fertilizer are broken-down by soil microbes, which aren't very active until the soil temperatures are warmer.
You'll need the results of a laboratory soil test to determine if you can (legally) use a lawn fertilizer formulation that has phosphorus in it (the P in the N-P-K nutrient analysis). If the test shows a P deficiency, then you can use a "starter" fertilizer (which will have P in it); if not, then a P-free fertilizer would be needed. We can help to interpret soil test results if desired. (Testing is mainly used for learning the nutrient content and acidity/pH. The lab will probably return some auto-generated fertilization recommendations along with the results, but bear in mind that they don't necessarily adjust those recommendations to comply with Maryland law, so use the UMD fertilization rates as your guide. The lab will also typically provide lime application rates if the pH needs adjusting, and those are fine to use as given.)
We have many web pages about all aspects of lawn care and maintenance that you can explore. They focus on tall fescue since that is the grass type recommended for most Maryland yards. In the coming months, we hope to drastically consolidate our lawn content into new web pages, but when that happens, we will try to have all of the old web page addresses redirect to the new pages; or, the content will still be easy to find, so you won't miss out on it if you need to check it again closer to lawn care season in autumn.
Miri
Hi Miri,
WOW, this is so helpful! Thank you for taking the time to provide such a thoughtful and helpful response. I will focus on seeding bare spots and sending off a soil sample so I am ready to fertilize in a few weeks. :)
Would you recommend aerating prior to fertilizing? Or should I wait until fall to aerate? If I fertilize in the spring, is it okay to skip fertilizing in the fall?
Thanks again!
You're welcome.
Core aerating can wait until just prior to seeding in fall, though if the lawn is badly compacted, you can probably do it in mid- to late spring as long as the lawn is in active growth. It's really best to focus fertilization efforts on fall, as that is when it will benefit the turf the most. A starter fertilizer (assuming soil test results allow it) is helpful in getting the seed established as it matures, but aside from that initial circumstance, if you're going to skip any season, skip spring and fertilize only in the fall. You can aerate just before seeding and fertilizing, so the seed has good seed-to-soil contact once it's sown, which improves germination rates.
Miri
Core aerating can wait until just prior to seeding in fall, though if the lawn is badly compacted, you can probably do it in mid- to late spring as long as the lawn is in active growth. It's really best to focus fertilization efforts on fall, as that is when it will benefit the turf the most. A starter fertilizer (assuming soil test results allow it) is helpful in getting the seed established as it matures, but aside from that initial circumstance, if you're going to skip any season, skip spring and fertilize only in the fall. You can aerate just before seeding and fertilizing, so the seed has good seed-to-soil contact once it's sown, which improves germination rates.
Miri
Thank you so much, Miri! This is extremely helpful. I will seed bare spots now, but wait until fall to aerate, overseed, and fertilize. I hope you have a great weekend!
Thank you, and you're welcome!
